Message2447

This patch allows the programmer to specify the
signatures of generated proxy methods of classes in
jython.  For example (from the test):

>>> class Bar(java.lang.Object):
...  def __init__(self, key):
...    self.message = 'hello!'
...    self.key = key
...  def hello(self):
...    self.message = 'hi'
...  def storeObj(self, something):
...    self.obj = something
...  def sum(self, a, b):
...    return a+b
...  sum.sig = ('i', ['i', 'i'])
...  def storeMe(self, str):
...    self.message = str
...  storeMe.sig = (None, [java.lang.String])

winds up with something like:

public class Bar extends Object {
  // constructors still the same

  public Object hello() {...}
  public Object storeObj(Object something) {...}
  public int sum(int a, int b) {...}
  public void storeMe(String str) {...}
}